Hypothyroidism Flashcards
1
Q
What is the definition of hypothyroidism?
A
Low activity of the thyroid gland
2
Q
How common is hypothyroidism?
A
Overall UK prevalence of over 2% in woman and under 0.1% in men
3
Q
What is the pathophysiology of hypothyroidism?
A
- TRH (Thyroid releasing hormone) is produced in the hypothalamus
- = pituitary gland secretes thyroid stimulating hormone (TSH)
- = THS stimulates growth and activity of the thyroid follicular cells
- Inorganic iodine → T3 (active) and T4 (prohormone) is released
- More T4 is produced but converted in peripheral tissue
- T3 binds to specific nuclear receptors on target cells
- Primary: disease of the thyroid
- Secondary: hypothalamic-pituitary disease
4
Q
What are the risk factors/aetiology of hypothyroidism?
A
- Woman
- Congenital
- Family history
- Autoimmune
- Hashimoto’s thyroiditis – most common in late middle age woman
- Postpartum thyroiditis (after pregnancy)
- Hypopituitarism
- Iodine deficiency
- Dyshormonogenesis – rare. Genetic defect in the synthesis of thyroid hormones
- Anti-thyroid drugs e.g. carbimazole
- Infective thyroiditis e.g. viral (de Quervains)
- Tumour
- Drugs: amiodarone, lithium
- Post-surgery
- Radiation
5
Q
What are the signs/symptoms of hypothyroidism?
A
- Tiredness
- Bradycardia
- Weight gain
- Cold intolerance
- Cold peripheries
- Goitre
- Depression
- Dry brittle hair and skin
- Loss of outer 1/3 of eyebrows
- ‘Peaches and cream’ appearance
- Muscle weakness
- Carpal tunnel
- Slow reflexed
- Poor libido
- Amenorrhoea
- Constipation
- Periorbital oedema/puffy eyes
6
Q
What diseases present similarly to hypothyroidism?
A
- Depression
- Anaemia
- Alzheimers dementia
7
Q
What investigations would be conducted if hypothyroidism was suspected?
A
- TFTs – immunoasssays for free T4, T3 and TSH
- ECG
- FBC for anaemia
8
Q
What is the surgical treatment for hypothyroidism?
A
Removal of tumour (if that is the cause)
9
Q
What is the pharmacological treatment for hypothyroidism?
A
Levothyroxine
10
Q
What is the non pharmacological treatment for hypothyroidism?
A
Non pharmacological • Screening for congenital hypothyroidism
